LightCraft has no colour matrix for Nikon cameras. Because of this, NEF
files showed colours that were too gray and too green.
- Colour: LightCraft now calculates a colour matrix and a tone curve from
the JPEG preview in each NEF file. Sony ARW files use the same
procedure and the same quality checks. White balance is relative to
the as-shot look, as for ARW files.
- One function, camera_preview::file_local_look, selects the formats for
the fit and for the relative white balance. Photo::relative_wb in the
catalog uses the same formats.
- Black level: Nikon stores the black level (maker note 0x003d) in
14-bit units, also in 12-bit files. The decoder read it as a 12-bit
value. Because of this, 12-bit files from the D750, D780, D850, D7500
and Z 50 were too dark. Now the decoder divides the value by 4 for
12-bit files.
- The corpus gets the D7500 12-bit and 14-bit lossless samples. A test
compares their levels. The render cache version increases to 9.
Results on 13 NEF files that LightCraft can decode: LightCraft accepted
the fit for all 13 files. The mean colour difference from the camera
JPEG (CIE76 dE) decreased from 13-46 to 2.9-7.8. One file with mixed
light improved by a small quantity only (12.7 to 12.0).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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